If you look at the sizes of the Linebackers Saban has brought in ( Spragan, Crowder, Turner ) and look at our linebackers that were heare previous ( Thomas, Seau, Moore, Pope, Ayanbadejo, Jenkins, etc. ), you will ifnd only one ( Seau ) actually matches up physically with the new guys.
Because of that, I think the backups and special teamers will be gone. Obviously Zach will stay and I think Moore might as well since he was such a high pick, but the others could be in jeopardy.
Seau, Thomas, Spragan will probably shake out to be your starters with Moore, Crowder, Pope and maybe Turner as the backups/special teamers.
Remember, Belichick kept a lot of LB's. At one point, he had 12 on the roster. However, the difference is that we have JT and David Bowens. Both of whom can line up at LB when we show some 3-4 looks. Right there that gives us two more "linebackers" so the need to keep a bunch is negated, especially if they aren't versatile enough to switch in and out of schemes.
4-3 look will feature something like this:
Taylor, Traylor, Carter, Holliday/Bowens
Seau, Thomas, Spragan
3-4 could look like so:
Holliday, Traylor, Carter
Spragan, Thomas, Seau, Taylor
Obviously Crowder, Roth and Bowens will be brought into the mix on both as well. But you can see that with our versatility with Taylor and Carter, that we could, in theory, line up in our base defense and the shift right into a 3-4 before the snap if needed. Saban has the players available to him to do this and talk about confusing as hell to the QB's.